1. Field of the Invention
The present invention relates to an air conditioner for a vehicle for air-conditioning a temperature environment within a vehicle compartment.
2. Description of the Related Art
A conventional air conditioner for a vehicle is used to air-condition a temperature environment within a vehicle compartment. The conventional air conditioner generally comprises a refrigeration cycle for circulating a refrigerant to thereby exchange heat between refrigerant and air, and a hot water line for exchanging heat using engine cooling water heated by heat that is exhausted from an engine.
In the conventional air conditioner for a vehicle, in an air passage within a vehicle compartment (which is hereinafter referred to as a within-vehicle-compartment air passage) into which the inside air and outside air can be selectively introduced, there are disposed an evaporator serving as a heat absorbing within-vehicle-compartment heat exchanger to be incorporated into the refrigeration cycle, and a heater core which serves as a heat generator and is incorporated into the hot water line. And, in case where the heat of the air flowing through the within-vehicle-compartment air passage is absorbed into the refrigerant existing within the evaporator, there is produced the cool air; and, in case where the air flowing through the within-vehicle-compartment air passage is heated by the heater core, there is produced the warm air. Also, in case where the rate between the cool air and warm air is adjusted by an air mix door, the temperature within the vehicle compartment can be adjusted.
By the way, in the above-structured conventional air conditioner for a vehicle, since the warm air is produced by the heater core which uses the engine cooling water as a heat medium, in a state where the temperature of the engine cooling water is not yet sufficiently high, for example, just after the engine is started, or when the running load is small, the temperature within the vehicle compartment cannot be raised up to a satisfactory level.
In order to cope with the above problem and thus enhance the heating performance, there are proposed air conditioners for a vehicle which are respectively disclosed in JP-A-9-175140 and JP-A-10-44742. In these air conditioners for a vehicle, a sub-condenser serving as a heat radiating within-vehicle-compartment heat exchanger for radiating the heat of the refrigerant into the air existing within the vehicle compartment is incorporated into the refrigeration line. And, the sub-condenser, together with the evaporator and heater core, is disposed in the above-mentioned within-vehicle-compartment air passage.
In the thus-structured air conditioners for a vehicle, since the warm air is produced not only by the heater core using the engine cooling water as a heat medium but also by the sub-condenser using the refrigerant as the heat medium, even in a state where the temperature of the engine cooling water is not yet sufficiently high, for example, just after the engine is started, or when the running load is small, the temperature within the vehicle compartment can be raised relatively rapidly.
Recently, the atmosphere of the space within the vehicle compartment has been made more and more comfortable and, with the increasing comfort of the vehicle compartment, there has been raised the need to enhance the performance of the air conditioner for a vehicle, especially, there has been strongly raised the need to further enhance the quick heating performance of the air conditioner for raising the temperature within the vehicle compartment quickly.
In the above-mentioned air conditioners for a vehicle, as a factor in hindering the further enhancement in the quick heating performance thereof, there can be pointed out the fact that, when the air conditioners for a vehicle are started, because the temperature load of the sub-condenser is low, the discharge pressure (Pd) of the refrigerant is hard to rise.
To enhance the temperature load of the sub-condenser, it is very effective to transmit heat from another heat source to the sub-condenser. According to an air conditioner for a vehicle disclosed in JP-A-10-44742, since, in a within-vehicle-compartment air passage, a heater core is disposed upstream of a sub-condenser, the heat of the heater core can be transmitted to the sub-condenser through the air flowing through the within-vehicle-compartment air passage, which makes it possible to enhance the temperature load of the sub-condenser.
However, during the time until the temperature of engine cooling water rises up to a specified value, in case where the air is allowed to flow through the within-vehicle-compartment air passage, the temperature of the air is lowered on the contrary. For this reason, during this time, preferably, the air may be prevented from flowing through the within-vehicle-compartment air passage. That is, in such case, since the heat of the heater core is not transmitted to the sub-condenser, the temperature load of the sub-condenser cannot be enhanced. Accordingly, a state, in which the refrigerant discharge pressure is hard to rise, continues for a given period of time, which makes it difficult to enhance the quick heating performance of the vehicle air conditioner further.
Also, in a state where the temperature load of the sub-condenser is low and the refrigerant discharge pressure is hard to rise, the efficiency of use of the refrigerant in the refrigeration cycle is lowered. Therefore, it is necessary to increase the enclosure amount of the refrigerant to a certain degree, and, as a liquid tank for holding therein a liquid-phase refrigerant temporarily, it is necessary to use a relatively-large-sized liquid tank, which provides a very great disadvantage in reducing the size and weight of the whole air conditioner for a vehicle.
An object of the present invention has been made to solve the above-mentioned drawbacks found in the conventional air conditioner for a vehicle. Accordingly, it is an object of the invention to provide an air conditioner for a vehicle which is excellent in the rapid heating performance and is able to realize reduction in the size and weight of the whole air conditioner for a vehicle.
In attaining the above object, according to a first aspect of the invention, there is provided an air conditioner for a vehicle, comprising: a compressor for compressing a refrigerant sucked therein and jetting out the compressed refrigerant therefrom; an outside-vehicle-compartment heat exchanger for radiating the heat of the refrigerant to the outside air; a heat radiating within-vehicle-compartment heat exchanger disposed in a within-vehicle-compartment air passage into which the inside air and the outside air can be introduced selectively for radiating the heat of the refrigerant to the air flowing through the within-vehicle-compartment air passage; an expander for expanding the refrigerant the heat of which has been radiated by at least one of the outside-vehicle-compartment heat exchanger and heat radiating within-vehicle-compartment heat exchanger; a heat absorbing within-vehicle-compartment heat exchanger disposed upstream of the heat radiating within-vehicle-compartment heat exchanger in the within-vehicle-compartment air passage for allowing the refrigerant expanded by the expander to absorb the heat of the air flowing through the within-vehicle-compartment air passage; and, a heat generator disposed in the within-vehicle-compartment air passage, wherein the heat radiating within-vehicle-compartment heat exchanger is disposed at a position which permits reception of the heat from the heat generator.
According to the first aspect of the invention, the refrigerant compressed by and jetted out from the compressor is supplied to at least one of the outside-vehicle-compartment heat exchanger and heat radiating within-vehicle-compartment heat exchanger, where the heat of the refrigerant is radiated. And, the refrigerant, the heat of which is radiated by at least one of the outside-vehicle-compartment heat exchanger and heat radiating within-vehicle-compartment heat exchanger, is supplied to and expanded by the expander.
The refrigerant expanded by the expander is supplied to the heat absorbing within-vehicle-compartment heat exchanger, where the refrigerant absorbs the heat of the air flowing through the within-vehicle-compartment air passage. And, the refrigerant, which has absorbed the heat of the air flowing through the within-vehicle-compartment air passage, is sucked into the compressor again. This series of cycles are repeated continuously.
In these cycles, in case where the air is introduced into the within-vehicle-compartment air passage, when the air passes through the heat absorbing within-vehicle-compartment heat exchanger disposed in the within-vehicle-compartment air passage, the heat of the air is absorbed by the refrigerant existing in the heat absorbing within-vehicle-compartment heat exchanger and the air is thereby dehumidified, so that the air turns into the cold air. Also, when the air passing through the within-vehicle-compartment air passage passes through the heat radiating within-vehicle-compartment heat exchanger and a heat generator respectively disposed in the within-vehicle-compartment air passage, the present air not only absorbs the heat of the refrigerant existing in the heat radiating within-vehicle-compartment heat exchanger but also absorbs the heat from the heat generator to be thereby heated, so that the air turns into the warm air.
Here, in the vehicle air conditioner according to the first aspect of the invention, since the heat radiating within-vehicle-compartment heat exchanger is disposed at a position which permits reception of the heat from the heat generator, even in a state where the air does not flow in the within-vehicle-compartment air passage, the heat from the heat generator is transmitted to the heat radiating within-vehicle-compartment heat exchanger. Due to this, the temperature load of the heat radiating within-vehicle-compartment heat exchanger can be increased, which makes it possible to raise the discharge pressure of the refrigerant rapidly.
Now, according to a second aspect of the invention, in an air conditioner for a vehicle as set forth in the first aspect of the invention, there are further included a first refrigerant line for supplying the refrigerant jetted out from the compressor to the expander through the outside-vehicle-compartment heat exchanger and allowing the refrigerant to be sucked into the compressor through heat absorbing within-vehicle-compartment heat exchanger; a second refrigerant line for supplying the refrigerant jetted out from the compressor to the expander through the heat radiating within-vehicle-compartment heat exchanger and allowing the refrigerant to be sucked into the compressor through the heat absorbing within-vehicle-compartment heat exchanger; and, a switch capable of selectively switching the first refrigerant line and second refrigerant line over to each other.
In the vehicle air conditioner according to the second aspect of the invention, when the first refrigerant line is selected by the switch, the refrigerant jetted out from the compressor is supplied to the outside-vehicle-compartment heat exchanger but is not supplied to the heat radiating within-vehicle-compartment heat exchanger. And, the refrigerant, the heat of which has been radiated by the outside-vehicle-compartment heat exchanger, is supplied to the expander; and, when the refrigerant passes through the heat absorbing within-vehicle-compartment heat exchanger, the refrigerant absorbs the heat of the air flowing through the within-vehicle-compartment air passage and, after then, the refrigerant is sucked into the compressor again.
On the other hand, when the second refrigerant line is selected by the switch, the refrigerant jetted out from the compressor is supplied to the heat radiating within-vehicle-compartment heat exchanger but is not supplied to the outside-vehicle-compartment heat exchanger. And, the refrigerant, the heat of which has been radiated by the heat radiating within-vehicle-compartment heat exchanger, is supplied to the expander; and, when the refrigerant passes through the heat absorbing within-vehicle-compartment heat exchanger, the refrigerant absorbs the heat of the air flowing through the within-vehicle-compartment air passage and, after then, the refrigerant is sucked into the compressor again.
Now, according to a third aspect of the invention, in an air conditioner for a vehicle as set forth in the first or second aspect of the invention, there are further included a third refrigerant line for supplying the refrigerant jetted out from the compressor to a second expander not connected to the heat absorbing within-vehicle-compartment heat exchanger through the heat radiating within-vehicle-compartment heat exchanger and allowing the refrigerant not only to bypass the heat absorbing within-vehicle-compartment heat exchanger but also to be sucked into the compressor; and, a switch capable of switching the selection of the third refrigerant line.
In the vehicle air conditioner according to the third aspect of the invention, when the third refrigerant line is selected by the switch, the refrigerant jetted out from the compressor is supplied to the heat radiating within-vehicle-compartment heat exchanger; and, the refrigerant, the heat of which has been radiated by the heat radiating within-vehicle-compartment heat exchanger, is supplied to the second expander not connected to the heat absorbing within-vehicle-compartment heat exchanger. And, the refrigerant, which has been expanded by the second expander not connected to the heat absorbing within-vehicle-compartment heat exchanger, bypasses the heat absorbing within-vehicle-compartment heat exchanger and is then sucked into the compressor again.
Now, according to a fourth aspect of the invention, in an air conditioner for a vehicle as set forth in the third aspect of the invention, in the third refrigerant line, there is disposed an inter-refrigerant heat exchanger for exchanging heat between the refrigerant expanded by the second expander and the refrigerant flowing through the front stage of the second expander.
In the vehicle air conditioner according to the fourth aspect of the invention, when the third refrigerant line is selected by the switch, the inter-refrigerant heat exchanger disposed in the third refrigerant line exchanges heat between the refrigerant expanded by the second expander not connected to the heat absorbing within-vehicle-compartment heat exchanger and the refrigerant flowing through the front stage of the second expander. And, the refrigerant, which has absorbed heat through this heat exchange operation, is sucked into the compressor.
Now, according to a fifth aspect of the invention, in an air conditioner for a vehicle as set forth in the third aspect of the invention, in the third refrigerant line, there is disposed an inter-refrigerant heat exchanger for exchanging heat between the refrigerant expanded by the second expander and the refrigerant in the front stage of the heat radiating within-vehicle-compartment heat exchanger.
In the vehicle air conditioner according to the fifth aspect of the invention, when the third refrigerant line is selected by the switch, the inter-refrigerant heat exchanger disposed in the third refrigerant line exchanges heat between the refrigerant expanded by the second expander not connected to the heat absorbing within-vehicle-compartment heat exchanger and the refrigerant in the front stage of the heat radiating within-vehicle-compartment heat exchanger the second expander. And, the refrigerant, which has absorbed heat through this heat exchange operation, is sucked into the compressor.
Now, according to a sixth aspect of the invention, in an air conditioner for a vehicle as set forth in any one of the first to fifth aspects of the invention, the heat generator is disposed upstream of the heat radiating within-vehicle-compartment heat exchanger in the within-vehicle-compartment air passage.
In the vehicle air conditioner according to the sixth aspect of the invention, the air flowing through the within-vehicle-compartment air passage absorbs the heat from the heat generator and is thereby heated; and, after then, the air absorbs the heat of the refrigerant in the heat radiating within-vehicle-compartment heat exchanger and is thereby heated further.
Now, according to a seventh aspect of the invention, in an air conditioner for a vehicle as set forth in any one of the first to sixth aspects of the invention, the heat radiating within-vehicle-compartment heat exchanger and a heat generator are formed as an integral body.
In the vehicle air conditioner according to the seventh aspect of the invention, the heat from the heat generator is transmitted directly to the heat radiating within-vehicle-compartment heat exchanger.
Now, according to an eighth aspect of the invention, there is provided an air conditioner for a vehicle, comprising at least: a compressor for compressing a refrigerant sucked therein and jetting out the compressed refrigerant to thereby allow the refrigerant to circulate; a within-vehicle-compartment heat exchanger disposed in a within-vehicle-compartment air passage, into which the inside air and the outside air can be introduced selectively, in such a manner that the circulating refrigerant can be supplied to the within-vehicle-compartment heat exchanger; a heat generator disposed in the within-vehicle-compartment air passage; and, an expander for expanding the circulating refrigerant, wherein the within-vehicle-compartment heat exchanger is disposed at a position which permits reception of the heat from the heat generator.
In the vehicle air conditioner according to the eighth aspect of the invention, in case where the air is introduced into the within-vehicle-compartment air passage while the within-vehicle-compartment heat exchanger functions as a heat radiator, the air flowing through the within-vehicle-compartment air passage, when passing through the within-vehicle-compartment heat exchanger and a heat generator, not only absorbs the heat of the refrigerant in the within-vehicle-compartment heat exchanger but also absorbs the heat from the heat generator to be thereby heated, with the result that the air turns into the warm air.
Here, in the vehicle air conditioner according to the eighth aspect of the invention, since the within-vehicle-compartment heat exchanger is disposed at a position permitting reception of heat from the heat generator, even in a state where the air does not flow in the within-vehicle-compartment air passage, the heat from the heat generator is transmitted to a heat radiating within-vehicle-compartment heat exchanger. Thanks to this, the temperature load of the heat radiating within-vehicle-compartment heat exchanger can be increased, which makes it possible to raise the discharge pressure of the refrigerant rapidly.
Now, according to a ninth aspect of the invention, in an air conditioner for a vehicle as set forth in the eighth aspect of the invention, the heat generator is disposed upstream of the within-vehicle-compartment heat exchanger in the within-vehicle-compartment air passage.
In the vehicle air conditioner according to the ninth aspect of the invention, the air flowing through the within-vehicle-compartment air passage absorbs the heat from the heat generator and is thereby heated and, after then, the air absorbs the heat of the refrigerant in the within-vehicle-compartment heat exchanger functioning as a radiator and is thereby heated further.
Now, according to a tenth aspect of the invention, in an air conditioner for a vehicle as set forth in the eighth or ninth aspect of the invention, the within-vehicle-compartment heat exchanger and a heat generator are formed as an integral body.
In the vehicle air conditioner according to the tenth aspect of the invention, the heat from the heat generator is transmitted directly to the within-vehicle-compartment heat exchanger.
According to the first aspect of the invention, even in a state where the air does not flow in the within-vehicle-compartment air passage, the heat from the heat generator is effectively transmitted to the heat radiating within-vehicle-compartment heat exchanger to thereby be able to increase the temperature load of the heat radiating within-vehicle-compartment heat exchanger and thus raise the discharge pressure of the refrigerant rapidly. That is, the first aspect of the invention allows the present vehicle air conditioner to fulfill a very excellent quick heating performance.
Also, since the temperature load of the heat radiating within-vehicle-compartment heat exchanger can be increased and the discharge pressure of the refrigerant can be thereby raised rapidly, the use efficiency of the refrigerant can be enhanced and thus the quantity of the refrigerant to be enclosed can be reduced. Therefore, according to the first aspect of the invention, it is possible to realize reduction in the size and weight of the whole vehicle air conditioner.
According to the second aspect of the invention, in the cooling operation time, the first refrigerant line is selected; whereas, in the heating operation time, the second refrigerant line is selected. That is, in the cooling operation time, the heat radiating within-vehicle-compartment heat exchanger is not used. This can avoid an inconvenience that, in the cooling operation time, the refrigerant, the heat of which has been radiated by the outside-vehicle-compartment heat exchanger, can absorb the heat from the heat generator to thereby lower the cooling efficiency of the vehicle air conditioner.
According to the third aspect of the invention, in the heating operation time, the third refrigerant line is selected; that is, in the heating operation time, the heat absorbing within-vehicle-compartment heat exchanger is not used. This not only can eliminate the need of execution of complicated operations such as a high-accuracy inside air and outside air introduction operation necessary for prevention of the over-cooling of the heat absorbing within-vehicle-compartment heat exchanger in the heating operation time, but also allows the vehicle air conditioner to fulfill an excellent quick heating performance.
According to the fourth aspect of the invention, in case where the third refrigerant line is selected, since the temperature of the refrigerant to be sucked into the compressor can be raised effectively, the quick heating performance can be enhanced further.
According to the fifth aspect of the invention, in case where the third refrigerant line is selected, since the temperature of the refrigerant to be sucked into the compressor can be raised effectively, the quick heating performance can be enhanced further.
According to the sixth aspect of the invention, the transmission efficiency of the heat to be transmitted from the heat generator to the heat radiating within-vehicle-compartment heat exchanger can be enhanced, which makes it possible to enhance the quick heating performance still further.
According to the seventh aspect of the invention, the transmission efficiency of the heat to be transmitted from the heat generator to the heat radiating within-vehicle-compartment heat exchanger can be enhanced, which makes it possible to enhance the quick heating performance still further.
According to the eighth aspect of the invention, even in a state where the air does not flow in the within-vehicle-compartment air passage, the heat from the heat generator is effectively transmitted to the within-vehicle-compartment heat exchanger serving as a heat radiator to thereby be able to increase the temperature load of the present within-vehicle-compartment heat exchanger and thus raise the discharge pressure of the refrigerant rapidly. That is, the first aspect of the invention allows the present vehicle air conditioner to fulfill a very excellent quick heating performance.
Also, since the temperature load of the within-vehicle-compartment heat exchanger can be increased and the discharge pressure of the refrigerant can be thereby raised rapidly, the use efficiency of the refrigerant can be enhanced and thus the quantity of the refrigerant to be enclosed can be reduced. Therefore, according to the eighth aspect of the invention, it is possible to realize reduction in the size and weight of the whole vehicle air conditioner.
According to the ninth aspect of the invention, the transmission efficiency of the heat to be transmitted from the heat generator to the within-vehicle-compartment heat exchanger serving as a heat radiator can be enhanced, which makes it possible to enhance the quick heating performance still further.
According to the tenth aspect of the invention, the transmission efficiency of the heat to be transmitted from the heat generator to the within-vehicle-compartment heat exchanger serving as a heat radiator can be enhanced further, which makes it possible to enhance the quick heating performance still further.